Decontamination of alkali chloride baths containing nuclear materials by precipitation and distillation techniques; Uranyl chloride precipitation test

Ibe, Junya*; Mitani, Mao*; Takahatake, Yoko  ; Watanabe, So  ; Watanabe, Masayuki; Asanuma, Noriko*; Matsuura, Haruaki*

Development of pyroprocessing experiments on nuclear fuel materials has been conducted, and contaminated chlorides has been generated. The aim of this study is to develop a simple uranium separation method for decontamination of the salts. Oxides are added as oxygen donor in the salts, and then uranium is separated from the salt as precipitates. NaCl-2CsCl salts, lithium oxide and uranyl chloride were used as target salt baths, the precipitant and a surrogate material of the contamination, respectively for testing the precipitation process. The precipitates were evaluated by thermodynamic calculations. Uranium oxide was produced, by adding lithium oxide. However, it was also found that an excess of lithium oxide could react with sodium and cesium to produce uranates. Vacuum distillation process on contaminated chlorides has been conducted, and radioactive materials has been recovered.